Comparison Of The Earthquake Responses Of Super-high-rise Building Structures Based On Different Seismic Design Spectra

According to statistics,over 40% of the world's super high-rise buildings are located in China.The performance of long-period structure under long period ground motion has attracted wide attention and research from scholars.Some of the results are written in the standard documents,and the difference in the application of these research results is a topic urgently to be studied.In this paper,two typical height engineering structures are selected as the research object with the Etabs model established.The time history analysis of the long-period ground motion recorded in the Wenchuan earthquake and the East Japan earthquake is carried out.And the recommended design spectrum in China,Japan and the United States are employed to investigate six structural corresponsive macroeconomic indicators of the structure.By comparing the differences between algorithms,the stability of the algorithm and the difference between the three algorithms,the reliability of the long period seismic design spectrum is evaluated and the main conclusions are obtained.(1)Comparison between the maximum structural vertex displacement and the maximum base shear response,based on the long-period segments stipulated in the Japanese and Chinese design codes,the displacement spectra increase significantly as the vibrational period increases,which is not consistent with the statistical attenuation characteristics and the physical meaning of the displacement response spectrum.The maximum structural vertex displacement of longperiod building structures,which are calculated using the mode-superposition response spectrum method in the design spectra stipulated in the Japanese and Chinese seismic design codes,are significantly larger than the average result calculated based on the dynamic timehistory analysis method.The differences between the displacements calculated based on the design spectrum stipulated in the US seismic design code or the proposed design spectrum and the results calculated based on the time-history analysis are relatively small,which is more reasonable.Taking into account the site conditions,by increasing the maximum value of the acceleration-sensitive segment in the short-period segment and increasing the site's characteristic period,the proposed design spectrum can better characterize the influence of the higher-order vibrational modes in the long-period building structure.For the large long-period building structures,the maximum displacement responses calculated by Chinese standard spectrum increase as the damping ratio increases,whereas the maximum base shear forces do not change significantly.This indicates that the long period segment of the design spectrum in the Chinese seismic design code is not reasonable.For large long-period building structures,as the damping ratio increases,the proportion of the damping force in the internal force of the structural system increases and thus cannot be neglected.Therefore,the reduction ratio of damping force in the long period of the response spectrum should be reduced appropriately.(2)Comparison of four structural indexes along the floor,including the distribution of the maximum story shear / story drift / story overturning moment /story displacement along the floor.Generally,the simulation results can satisfy the sort of time-history analysis <proposed design method?US seismic design code < Chinese seismic design code < Japanese seismic design code,and with the increase of damping ratio,the responses calculated by Chinese standard spectrum exceed Japanese standard spectrum.The longer the basic period of the structure,the phenomenon is more obvious.It is found that the stability of the proposed design spectrum is the best,but when the basic period of the structure is longer and the damping ratio is large,the stability of the proposed design is decreased,which is equivalent to the Chinese standard spectrum.For Chinese and Japanese standard spectrum,the discreteness of two-way input incentive results will increase significantly,while the discreteness of US seismic design code and proposed design spectrum is basically the same.For the performance of the algorithm under different damping ratios,the excitation one-way input result is slightly less than the two-way input result,and the difference will decrease with the increase of damping ratio.Japanese standard spectrum is most sensitive to one-way and two-way input,while the US standard spectrum and the proposed design spectrum are well simulated in both situations.For the large long-period building structures,the results of Chinese standard spectrum are abnormal,that is,the index increases with the increase of damping ratio,which does not conform to the statistical law.For the longer period structure,Chinese standard spectrum appears abnormal,that is,the index increases with the increase of damping ratio,and does not conform to the statistical law.